When a notebook computer is connected to via a universal serial bus (referred to as USB) interface, the users of the notebook computer can surf the web anywhere anytime, using a universal subscriber identity module (referred to as USIM)/subscriber identity module (referred to as SIM) card to be registered in the mobile network and a data card (including USB modem) to be connected to the Internet. The third generation mobile communications (referred as to 3G) network has been very popular in foreign countries, and the web surfing speed by using a data card can be as high as that of the broadband. With the continuous maturity of domestic 3G network services in China, more and more users will use data cards.
In addition to using the mobile communication network to access the Internet, a data card also has functions of receiving and sending short messages and storing business cards list. Therefore, a lot of private information of users may be contained in the data card. Since the storage space of a USIM card is limited, it is impossible to save all the private information in the USIM card. If the information is stored directly in the computer, it is unsafe because the computer virus is rampant nowadays. In order to protect these data, the users urgently need a method for storing the data information safely.
There are methods for hiding the menu and data in the mobile terminal exist in relevant art, but for the software installed in the computer, even if the function menu is concealed, the security level of the user's data information files stored in the computer is still very low and attackers can acquire the information easily. What's more, there also are methods for protecting the information in the mobile terminal by means of encryption. However, the security of encrypted information is relatively low. In addition, there also are methods adopting short message instruction distant control to encrypt or clean the specific information in a cell phone, thereby playing a certain protective action to the information in a stolen cell phone, however, by these methods the information of a data card in use is only protected by encryption, which cannot be very effective. It can be concluded that the security described above is relatively low, which cannot satisfy the needs of users well.